Khaled Ismail Karaky

Associate professor
Chemistry - Biochemistry department - Section V - Nabatiyeh
Speciality: Chemistry
Specific Speciality: chimie et physico-chimie des polymères
Interests: Sports, geographical research, arts and culture, films, hunting....

2003 - 2006:

University of Pau
Polymer Chemistry


Publications 9 publications
Jalal Dweik, Mahmoud Srour, Khaled Karaky, Marwan Kobeissi, Wissam Joumaa, Khalil Abou-Saleh Molecular Simulation of Ion Transport at the Water/Vapor Interface Open Journal of Physical Chemistry 2012

Molecular dynamics was used to quantify the role of the size, charge and polarisability of F–, Cl–, Br–, I– and Na+ ions in their distribution in the water/vapour interface system. Our results show that the larger polarizable anions I– and Br– is attracted to the surface which is traced back to surface-modified ion hydration, while the F– was repelled from the interface and the Cl– occupied the total volume of the water slab. Moreover, by artificially increasing the ions charge, anions were localized to the center of the water slab. These results demonstrate that the effect of polarizability cannot be neglected in the transport mechanism.

Khaled Karaky1, Gérald Clisson1, Gunter Reiter2 and Laurent Billon1,* Semi-Crystalline Macromolecular Design by Nitroxide Mediated Polymerization Macromolecular Chemistry and Physics 2008

The syntheses of PODA-b-PMA and PODA-grad-PMA copolymers using NMP are reported for the first time. The gradient copolymerization of ODA and MA was performed in a semi-batch system with a continuous addition of MA during ODA polymerization. The results showed that the semi-batch NMP proceeded in a living fashion, producing well-defined copolymers with narrow polydispersities and controlled molecular weights. The potentially semicrystalline copolymers were characterized by techniques such as 1H NMR, SEC and DSC. Their surface crystallization has also been studied by AFM.

Khaled Karaky,a Cyril Brochon,*a Guy Schlattera and Georges Hadziioannou*a pH-responsive supramolecular “sliding” hydrogels based on poly(ethyleneimine-b-ethylene oxide-b-ethyleneimine) and ß-cyclodextrin: synthesis and swelling behaviour Soft Matter 2008

A new type of pH-switchable supramolecular sliding gel has been synthesized, based on polyrotaxanes of polyethyleneimine-block-poly(ethylene oxide)-block-polyethyleneimine block copolymer and α-cyclodextrin. The three dimensional supramolecular network was obtained by an inter-molecular crosslinking reaction between CDs belonging to two different polyrotaxanes via1,1′-carbonyldiimidazole. Higher gel equilibrium swelling has been observed in acidic medium than in basic medium. This behaviour is explained by the ionization of EI units leading to electrostatic repulsion of the PEI blocks.

Khaled Karaky2, Christophe Derail1, Gunter Reiter2 and Laurent Billon1,* Tuning the surface/bulk properties by the control of the amphiphilic profile in gradient copolymer Macromolecular Symposia 2008

Nitroxide Mediated Radical Polymerization (NMP) combined with the Semi-Batch process is used for synthesize poly(N,N-Dimethylacrylamide-grad-Butyl acrylate), called poly(DMA-grad-BuA), in the presence of SG1 as control agent and the alkoxyamine (MAMA) as initiator. The instantaneous composition is used to characterize the gradient copolymers. The variation of the addition rate of DMA influences on the incorporation of DMA in the macromolecular chains. The thermal/rheological properties of gradient copolymers in bulk are also studied and discussed in relation with their local structure.

Khaled Karaky,a Eve Péré,b Claude Pouchan,b Hélène Garay,c Abdel Khoukh,a Jeanne François,a Jacques Desbrièresa and Laurent Billon*a Gradient or statistical copolymers by batch nitroxide mediated polymerization: effect of styrene/methyl acrylate feed New Journal of Chemistry 2006

Monomer reactivity ratios in controlled radical copolymerization of styrene (S) and methyl acrylate (MA) monomers at 120 °C were determined. The Fineman–Ross method was used to calculate rs and rMA. Using this method, monomer reactivity ratio values of 0.89 and 0.22 were calculated for styrene and methyl acrylate, respectively. Because of the different reactivity ratios between the two monomers, and according to the molar fractions of two monomers, S/MA statistical or gradient copolymers were synthesized by nitroxide-mediated polymerization. Indeed, for different monomer ratios, the same statistical or gradient copolymers can be obtained by batch nitroxide mediated polymerization. These copolymers have been characterized by 1H nuclear magnetic resonance and size exclusion chromatography, and evolution of the composition has been correlated with the glass transition temperature measured by differential scanning calorimetry. Integrated intensities of the three observed peaks of (–OCH3) group in the 1H NMR spectra were used to determine the MA/MA/MA, MA/MA/S and S/MA/S triad sequences in the copolymers. Specific organization at the air/polymer interface of such copolymers has also been demonstrated by comparison between classical and attenuated total reflection (ATR) Fourier transform infra-red spectra.

Khaled Karaky,a Eve Péré,b Claude Pouchan,b Jacques Desbrières,a Christophe Déraila and Laurent Billon*a Effect of the synthetic methodology on the molecular architecture : From Statistical to Gradient copolymers Soft Matter 2006

Styrene–butyl acrylate (S–BuA) copolymers were synthesized by nitroxide-mediated controlled radical polymerization using an alkoxyamine as an initiator. Using different synthetic methodologies, statistical copolymers were be obtained by batch nitroxide mediated polymerization while the gradient composition was a forced gradient by continuous addition of S during BuA polymerization (semi-batch process). These gradient copolymers have been studied by 1H NMR and size exclusion chromatography to characterize the gradient composition molecular structure. The evolution of the composition was correlated with the glass transition temperature (Tg) of the copolymers. The gradient copolymers exhibit one Tg with a value in between the Tg of polystyrene and poly(butyl acrylate), indicating that the materials did not present well defined microphase separation. Specific organization at the air–polymer interface of such copolymers has also been demonstrated by comparison between classical and attenuated total reflection (ATR) Fourier transform infra-red spectra. This bulk soft matter assembly was confirmed by AFM analysis, which showed a different morphology at the surface and in the bulk following removal of the top layer. Moreover, for the most well defined gradient composition, a specific nano-structuring was demonstrated by small angle neutron scattering. The preliminary rheological properties of these gradient copolymers were studied and are discussed in relation with their molecular structure.

Khaled Karaky ,† Laurent Billon ,*† Claude Pouchan ,‡ and Jacques Desbrières † Amphiphilic Gradient Copolymers Shape Composition Influence on the Surface/Bulk Properties Macromolecules 2006

Nitroxide-mediated radical polymerization (NMP) combined with the semibatch process was used to synthesize poly(N, N-dimethylacrylamide-grad-butylacrylate), called poly(DMA-grad-BuA), in the presence of SG1 as a control agent and the alkoxyamine (MAMA) as an initiator. The pseudo-instantaneous composition was used to characterize the gradient copolymers. The variation of the addition rate of DMA influences the incorporation of DMA in the macromolecular chains. The preliminary surface characterization by the measure of the static water contact angle of the gradient copolymers films indicated that the monomer unit sequence in the polymer chain strongly influences the surface properties. The rheological properties of gradient copolymers in bulk were also studied and discussed in relation to their local structure.

Karaky, K; Raynaud, S; Billon, L; Francois, J and Chreim, Y. Organosoluble star polymers from cyclodextrin core Journal of Polymer Science, Part A 2005

Well-defined star polymers were synthesized with a combination of the core-first method and atom transfer radical polymerization. The control of the architecture of the macroinitiator based on β-cyclodextrin bearing functional bromide groups was determined by 13C NMR, fast atom bombardment mass spectrometry, and elemental analysis. In a second step, the polymerization of the tert-butyl acrylate monomer was optimized to avoid a star–star coupling reaction and allowed the synthesis of a well-defined organosoluble polymer star. The determination of the macromolecular dimensions of these new star polymers by size exclusion chromatography/light scattering was in agreement with the structure of armed star polymers in a large range of predicted molecular weights. This article describes a new approach to polyelectrolyte star polymers by postmodification of poly(tert-butyl acrylate) by acrylic arm hydrolysis in a water-soluble system.

Yamama Chreim, Khaled Kharaki, Stéphanie Reynaud, Laurent Billon et Jeanne François Peracylation des cyclodextrines (α-CD et β-CD) par différents halogénures d’alkanoyle CNRS 2005

Les conditions optimales de per-estérification des cyclodextrines (β- et α-CD) par le bromure de bromopropionyle (BBP) et le chlorure de chloropropionyle (CCP) sont définies. La Pyridine (PY) a été utilisée à la fois comme catalyseur et comme solvant en présence de chloroforme. Les mécanismes réactionnels ont été étudiés pour différentes concentrations en réactifs et différents rapports X=[BBP]/[CD] et Y=[PY]/[BBP] et les produits de réaction ont été caractérisés par Résonance Magnétique Nucléaire 1H et 13C, spectrométrie de masse, Infra-Rouge à Transformée de Fourier et analyse élémentaire. On a observé que le BBP conduit à l’estérification complète de tous les groupes hydroxyles des β-CD et α-CD, mais que l’estérification par le CCP n’est pas quantitative avec une cinétique de réaction plus lente. L’optimisation de la per-estérification des cyclodextrines conduit à de nouveaux composés qui sont testés comme amorceurs de polymérisation radicalaire par transfert d’atome (ATRP) pour préparer des polymères en étoile à branches de poly(acrylate de tertio-butyle) bien définis.